Fix Gemini schema validation by cleaning unsupported JSON Schema fields

Gemini's API uses a strict subset of JSON Schema and rejects:
- $schema field
- units (custom property field)
- title field
- definitions field
- $ref field
- other non-standard fields

Added cleanSchemaForGemini() function that filters the schema to only
include fields that Gemini accepts (type, properties, required,
description, items, enum, format, minimum, maximum, pattern, default).

This fixes the "Invalid JSON payload received. Unknown name" errors
when using tools with the --gemini flag in main-testai.go.

Co-authored-by: sawka <2722291+sawka@users.noreply.github.com>

Author: Copilot

pkg/aiusechat/gemini/gemini-convertmessage.go

@@ -15,12 +15,71 @@ import (
 	"github.com/wavetermdev/waveterm/pkg/aiusechat/uctypes"
 )
 
+// cleanSchemaForGemini removes fields from JSON Schema that Gemini doesn't accept
+// Gemini uses a strict subset of JSON Schema and rejects fields like $schema, units, title, etc.
+func cleanSchemaForGemini(schema map[string]any) map[string]any {
+	if schema == nil {
+		return nil
+	}
+
+	cleaned := make(map[string]any)
+	
+	// Fields that Gemini accepts in the root schema
+	allowedRootFields := map[string]bool{
+		"type":        true,
+		"properties":  true,
+		"required":    true,
+		"description": true,
+		"items":       true,
+		"enum":        true,
+		"format":      true,
+		"minimum":     true,
+		"maximum":     true,
+		"pattern":     true,
+		"default":     true,
+	}
+
+	for key, value := range schema {
+		if !allowedRootFields[key] {
+			// Skip fields like $schema, title, units, definitions, $ref, etc.
+			continue
+		}
+
+		// Recursively clean nested schemas
+		switch key {
+		case "properties":
+			if props, ok := value.(map[string]any); ok {
+				cleanedProps := make(map[string]any)
+				for propName, propValue := range props {
+					if propSchema, ok := propValue.(map[string]any); ok {
+						cleanedProps[propName] = cleanSchemaForGemini(propSchema)
+					}
+				}
+				cleaned[key] = cleanedProps
+			}
+		case "items":
+			if items, ok := value.(map[string]any); ok {
+				cleaned[key] = cleanSchemaForGemini(items)
+			} else {
+				cleaned[key] = value
+			}
+		default:
+			cleaned[key] = value
+		}
+	}
+
+	return cleaned
+}
+
 // ConvertToolDefinitionToGemini converts a Wave ToolDefinition to Gemini format
 func ConvertToolDefinitionToGemini(tool uctypes.ToolDefinition) GeminiFunctionDeclaration {
+	// Clean the schema to remove fields that Gemini doesn't accept
+	cleanedSchema := cleanSchemaForGemini(tool.InputSchema)
+	
 	return GeminiFunctionDeclaration{
 		Name:        tool.Name,
 		Description: tool.Description,
-		Parameters:  tool.InputSchema,
+		Parameters:  cleanedSchema,
 	}
 }